Http.PostJsonAsync(string, object) need to return the response

[yan0lovesha]

Is your feature request related to a problem? Please describe.

Describe the solution you'd like

Currently only Http.PostJsonAsync() can deserialize the response body to type T. Most times we don't want to define a C# class to represent the response body. In this case people often call Http.PostJsonAsync() instead, but this one doesn't give any chance to access the response. I think either return a HttpResponseMessage or a string of the body are OK. A string body should be able to cover the most scenarios.

Describe alternatives you've considered

Additional context

[mkArtakMSFT]

Thanks for contacting us, @yan0lovesha.
We're tracking this issue as part of #10397